Creating PNG images from web content to be used by OverviewMode navigation

athena/activity/public/activity_view_model.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ATHENA_ACTIVITY_PUBLIC_ACTIVITY_VIEW_MODEL_H_
 #define ATHENA_ACTIVITY_PUBLIC_ACTIVITY_VIEW_MODEL_H_
 
 #include "athena/athena_export.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/strings/string16.h"
+#include "ui/gfx/image/image.h"

[oshima, 2014/09/22 16:10:27]

forward decl should be enough

[Mr4D (OOO till 08-26), 2014/09/23 19:07:33]

Done.

 
 typedef unsigned int SkColor;
 
-namespace gfx {
-class ImageSkia;
-}
-
 namespace views {
 class View;
 class Widget;
 }
 
 namespace athena {
 
 // The view model for the representation of the activity.
 class ATHENA_EXPORT ActivityViewModel {
  public:
@@ skipping 24 matching lines @@
   virtual views::View* GetContentsView() = 0;
 
   // Creates a custom widget for the activity. Returns NULL to use default
   // implementation.
   virtual views::Widget* CreateWidget() = 0;
 
   // Returns an image which can be used to represent the activity in e.g. the
   // overview mode. The returned image can have no size if either a view exists
   // or the activity has not yet been loaded. In that case
   // GetRepresentativeColor() should be used to clear the preview area.
+  // The ownership gets passed to the caller.
   // Note: We intentionally do not use a layer / view for this.
-  virtual gfx::ImageSkia GetOverviewModeImage() = 0;
+  virtual scoped_ptr<gfx::Image> GetOverviewModeImage() = 0;

[oshima, 2014/09/22 16:10:28]

Is there particular reason why this needs to be scoped_ptr?
The image data in gfx::Image is ref counted.

[sadrul, 2014/09/22 16:13:32]

Why this change?

[Mr4D (OOO till 08-26), 2014/09/23 19:07:33]

Hmm. I was under the misconception that Image was not auto managed, only
SkiaImage. Done.

[Mr4D (OOO till 08-26), 2014/09/23 19:07:33]

I have found the PNG decoding to be done with gfx::Image. According to
Image::ToImageSkia(): "The returned result is a weak pointer owned by and scoped
to the life of the Image.". So to keep ImageSkia we would have needed to add
some kind of release call. However it appeared to be much simpler if the caller
can use Image::ToImageSkia and release the bits on its own when done.

Makes sense - or do you see a better solution?

[oshima, 2014/09/24 00:40:00]

gfx::Image stores images in ImageStorage, which is refcounted and shared between
gfx::Image instances originated from the same instance.

I agree that the comment is a bit misleading. It simply means the returned point
is valid so long
as the gfx::Image(s) owning the image are live.

 
   // Prepares the contents view for overview.
   virtual void PrepareContentsForOverview() = 0;
 
   // Undoes any changes done by PrepareContentsForOverview().
   virtual void ResetContentsView() = 0;
 };
 
 }  // namespace athena
 
 #endif  // ATHENA_ACTIVITY_PUBLIC_ACTIVITY_VIEW_MODEL_H_